Nonwoven substrates, particularly tissue papers, are well known in the art. Tissue papers are commonly used as facial tissues, bath tissue, paper towels, napkins and wipes. More recently, synthetic nonwovens have been used in the shower as poofs for washing one's skin and as a disposable mophead for cleaning floors and other hard surfaces. Suitable body wash implements are disclosed in commonly assigned U.S. Pat. No. 5,650,384, issued Jul. 22, 1997 to Gordon et al., and commonly assigned Pat. Apps. WO 98/15262, WO 99/25318, WO 99/06793, all of which are incorporated herein by reference. Exemplary mops having disposable nonwoven substrates are illustrated by commonly assigned U.S. Pat. No. 6,101,661, issued Aug. 15, 2000 to Polieicchio et al., and U.S. Pat. No. Des. 409,343, issued May 4, 1999 to Kingry et al., both incorporated herein by reference, and by the mops marketed by the instant assignee as Swifter mops. Discrete apertured nonwoven substrates are also illustrated in commonly assigned U.S. Pat. No. 5,895,627, issued Apr. 20, 1999 to Trokhan, and incorporated herein by reference. Commonly assigned WO 98/11813, published Mar. 26, 1998 in the name of Sherry and incorporated herein by reference, discloses a cleaning implement having a wettable cleaning pad.
It has long been a goal in the art of making tissue paper to make tissue paper having lower density, also known as having higher bulk. One of the first attempts in the art to improve tissue by lowering the density is found in commonly assigned U.S. Pat. No. 3,301,746, issued Jan. 31, 1967 to Sanford et al. and incorporated herein by reference. Sanford et al. discloses through air dried paper having substantially lower overall density than that of conventional press felt dried tissue. U.S. Pat. No. 4,191,609, issued Mar. 4, 1980 to Trokhan, and incorporated herein by reference, discloses an improvement to low density, through air dried paper. This patent discloses paper made with a pattern of biaxially staggered low density zones which provides increased flexibility.
Yet another series of commonly assigned patents illustrate low density papermaking through the use of belts having photosensitive resin. This technology provided flexibility to the papermaking process which was previously unavailable. Exemplary patents showing such technology include commonly assigned U.S. Pat. No. 4,529,480, issued Jul. 16, 1985 to Trokhan; U.S. Pat. No. 4,637,859, issued Jan. 20, 1987 to Trokhan; U.S. Pat. No. 5,364,504, issued Nov. 15, 1994 to Smurkoski et al.; U.S. Pat. No. 5,529,664, issued Jun. 25, 1996 to Trokhan et al.; U.S. Pat. No. 5,679,222 issued Oct. 21, 1997 to Rasch et al.; U.S. Pat. No. 5,714,041 issued Feb. 3, 1998 to Ayers et al.; and U.S. Pat. No. 5,906,710, issued May 25, 1999 to Trokhan, and incorporated herein by reference.
Yet another technology purportedly achieving low density tissue is found in U.S. Pat. No. 5,932,068, issued Aug. 3, 1999 to Farrington, Jr. et al. This patent purports to make low density tissue without creping.
However, each of the aforementioned disclosures of tissue paper present a tissue paper to the user having only a single set of intensive properties. Intensive properties include but are not limited to density, thickness, coefficient of friction, volume (on a unit area basis), surface area (on a unit area basis) and void volume.
More particularly, the tissue paper of the prior art has only a single overall or bulk density. The user cannot significantly affect the density of the tissue paper once the manufacturing process is complete. However, there are times the user may desire tissue paper to be of a different density than that which is initially presented at the point of purchase. For example, the user may desire a higher density tissue paper for shipping and storage and a lower density tissue paper for the ultimate use. If so, it would be convenient for the consumer to have a sheet of tissue paper presented with a first density and transformable into a second and substantially lesser density.
Likewise, the user may desire the tissue paper to be transformed from a first volume to a second volume and/or thickness. The second volume and/or thickness may be greater than the first. The increase in volume and/or thickness may provide the benefit of a first and lesser volume and/or thickness for shipment and storage prior to the point of use by the consumer. At the point of use, the consumer may activate the tissue paper to a second and greater volume and/or thickness. Such increased volume and/or thickness provides the benefit, for example, the increased volume and/or thickness would provide hand protection for the user during use. This can be particularly advantageous when the product is used as a bath tissue or for cleaning other surfaces.
Likewise, the user is typically not able to significantly modify the surface area of the tissue paper once the manufacturing process is complete. As used herein, the term “surface area” refers to the amount of surface area, considering the topography, of the tissue paper as contained within a unit area flat planar projection of that tissue paper. Generally, this amount of surface area is greater than the surface area obtained by measuring the projected planar dimensions of the tissue paper. The user may desire a first surface area for shipment and storage, and a second surface area for use.
Likewise, the user may desire to have a tissue paper with multiple exposed edges which can provide for cleaning. The edges provide a scraping action for removal of the material to be cleaned. This can be particularly advantageous when the product is used as a bath tissue or other cleaning implement. It is believed that the greater surface area provided to the tissue paper of the present invention upon activation ultimately yields more usable area for cleaning. Particularly, each edge of the slit provides an opportunity for scraping foreign material from the surface to be cleaned. Foreign material can become entrapped in the voids between slits allowing for further efficacy in cleaning. This improved cleaning efficacy may manifest itself as an increase in the coefficient of friction of the tissue paper.
Likewise, if the tissue paper according to the present invention is to be used as a bath tissue, high void volume upon activation prophetically provides for improved flushability. One attempt in the art to make a toilet paper having improved flushability is found in U.S. Pat. No. 5,652,035, issued Jul. 29, 1997, to Tseng. This patent discloses a bath tissue paper divided into quadrants. Diagonally opposed quadrants have slits which are parallel. The tissue paper has two pairs of diagonally opposed quadrants. Each pair has slits which are mutually parallel to the slits in the diagonally opposed quadrant and mutually perpendicular to the slits in the adjacent quadrants. While this arrangement may provide improved flushability, it does not allow the consumer to readily activate the tissue paper by application of tensile forces. As the user grasps the tissue and pulls it apart, the slits which are perpendicular to the line of the tensile force will tend to open the tissue paper while the slits which are parallel to the application of the tensile force will generally not be extensible. The tissue will not properly activate as described below.
Commonly assigned U.S. Pat. No. 3,895,128, issued Jul. 15, 1975 to Gaisser, incorporated herein by reference, discloses a fabric conditioner article usable as a dryer-added fabric softener. Commonly assigned U.S. Pat. No. 3,944,694, issued Mar. 16, 1976 to McQueary, and U.S. Pat. No. 3,956,556, issued May 11, 1976 to McQueary, both incorporated herein by reference, disclose fabric conditioning articles having slits and perforations therein. These fabric conditioner articles are also usable as dryer-added fabric softeners. The purpose of the slits and perforations is to allow air flow through the fabric conditioning article, thereby preventing obstruction of the exhaust when used as a dryer-added fabric softener. If a substrate according to the present invention is to be used as a dryer-added fabric softener, activation of the substrate at the point of use provides a low density/high void volume substrate, particularly well suited for air flow therethrough during use in the dryer.
Another application of slitting technology is found in U.S. Pat. No. 5,667,871, issued Sep. 16, 1997, to Goodrich et al. Goodrich et al. uses an exemplary 70 pound natural Kraft paper to form filling material. The material is used to fill hollow spaces in packaging or the like. Likewise, U.S. Pat. No. 5,365,819, issued Nov. 22, 1994 to Maida et al., teaches a process for forming a packing material using a multitude of slits. The slits allow the material to be expanded into a three-dimensional shape that is both load-bearing and resilient.
Yet another example of the slitting technology is illustrated in U.S. Pat. No. 5,374,381, issued Dec. 20, 1994, to Schuld et al. Schuld et al. teaches an evaporative element or cartridge especially useful in humidifiers. The element comprises multiple layers of slit and expanded wicking material made of blotter-type paper. A metal layer or other frame is provided for structural strength.
A substrate according to the present invention may be used as a bath tissue, facial tissue, paper towel, napkin, rag, sponge, scrubby, poof, body wash, filter, face mask, pillow material, padding, insulation, packing material, bandage, wound dressing, dryer-added fabric softener, a core for absorbent products such as diapers, sanitary napkins or tampons, a drainage medium for outdoor use, bedding for plants, etc. The substrate, without regard to its end use, is activatable at the point of use or at an intermediate point in the manufacturing process.